Welcome

Welcome to Ballistics By The Inch, or 'BBTI' as people have taken to calling it.

Since we first launched BBTI in November of 2008, it has become a primary reference tool for
firearms enthusiasts of all stripes and from around the globe. Our initial research data
covered the relationship between barrel length and velocity for some 13 common handgun
calibers/cartridges. In response to the phenomenal popularity of the site, we’ve continued
to do testing, and have expanded the data to include an additional 8 handgun calibers/cartridges
(and a repeat of the .380 Auto tests with additional ammunition) as well as the .223 rifle
cartridge. We’ve also conducted a major study of the 'cylinder gap effect' on a revolver,
involving more than 6,000 rounds fired, as well as a comparison of the performance differences
between polygonal and traditionally rifled barrels. As always, all of our data is freely
available, though we happily accept donations (see button below left)and would greatly appreciate
your tangible support to help us continue the project.

Up above you’ll find links to four main pages:

Calibers/cartridges will take you to a list of all 22 different data sets. You
can just browse the charts, click on a given ammunition type listed in the header of each chart
for a graph of how that particular ammunition performed, or download the raw
data for your own use.

Cylinder gap will take you to the results of that study, which used an Uberti Single
Action Army clone in .38/.357 mag to examine velocity differences between three different cylinder
gaps (0.006", 0.001", and 'flush').

polygonal rifling will take you to the newest part of our site, documenting performance
comparisons between polygonal and traditionally rifled barrels in 9mm.

Real world guns will take you to a comprehensive list of all the firearms we used as
'benchmark' comparisons for results obtained from our T/C Encore test platform. You'll also
see "review" listed after a number of the guns, which will take you to a review of that particular
gun (or a closely related model) over at Guns.com written by Jim Downey of the BBTI team (who is
also a writer for Guns.com).

Along the left side there you'll find some more basic information about BBTI.

As we've noted previously, we have no illusions that our data is comprehensive. It is
meant to be indicative – giving an indication to the general relationships between barrel length
and velocity, or the effect of a cylinder gap, or how polygonal and traditionally rifled barrels
perform. It would be impossible (for us, at least) to test all the different
ammunition types available, or all the different firearms – particularly so when manufacturers of
ammunition and firearms are constantly tweaking and improving their products. So use the data
here to get an idea of what to expect, and perhaps as a jumping-off point for your own research.

Thanks for coming by.

Other Resources

BBTI is not the end-all of ballistics testing, just one more component
available for the common good. In addition to extensive discussion
about ballistics to be found at many gun forums, here are some other great
resources pertaining to ballistics testing you should check out. (And
if you would like to recommend a site to list here, please send an email.)

BrassFetcher:
excellent resource, with an emphasis on bullet performance in ballistic
gelatin

Terminal Ballistics
Research: Specializes in the research of cartridge & projectile performance,
using hard data gathered from 20 years of hunting game.

Acknowledgements

We'd like to personally and specifically thank Pat Childs at Fin & Feather in Iowa City, as he not only helped get most of our
ammunition and other supplies, he was the brilliant gunsmith who worked with us to make
this insane project much more practical. Without his help all of this would have
been much more difficult and perhaps impossible. Anyone who uses our data owes him
a debt of gratitude.

And thanks to our spouses, who were not just tolerant but enthusiastically supportive
of this rather nutty project.

Disclaimer

This project, and all of its results, is only our fault. We (well, Jim K,
mostly) paid for everything ourselves, and we did not receive any kind of sponsorship
or remuneration from anyone. We did all the work. We used products we
were either familiar with, or because they were what was available, and mentioning
them by name does not constitute an endorsement of any kind. Furthermore, the
data is provided purely for entertainment purposes - to better facilitate arguments
over what ammo or caliber or gun is "best." How you use the data is entirely
up to you. And if you think you could do better, feel free to spend the money
and do the work and publish your own results. Or not. Your choice.